Several processes for preparing 3-amino-2-hydroxypropionic acid derivatives (1) are known in the art. One representative is a process comprising a stereoselective addition reaction of a cyanide compound onto an aminoaldehyde derived from an amino acid [J. Chem. Soc., Chem. Commun., p. 938 (1989); Synthesis, p. 703 (1989); EP-B-341462; JP-A-02/17165; JP-A-02/28144; JP-A-02/56547; JP-A-08/165,274; JP-A-10/231,280]. However, the above process must use a cyanogen compound having a very high toxicity, and therefore, is problematic as an industrial production process.
Other processes, for example, a process comprising decomposing an optically active 2-azetidinone derivative obtained through a [2+2] cyclo addition of a chiral imine and a ketene compound [Tetrahedron Lett., vol. 31, p. 3031 (1990)], and a process comprising a stereoselective alkylation and a stereoselective amination of a chiral glyoxylate [J. Org. Chem., vol. 54, p. 4235 (1989)] are also known in the art. However, all these processes are also problematic as an industrial production process because they need many steps and complicated procedures, for example.
Furthermore, a process comprising stereoselectively alkylating a malic acid ester, selectively converting one of carboxyl groups into an azide, and then passing through a rearrangement reaction of Curtius type [EP-B-379288; Tetrahedron Lett., vol. 33, p. 6803 (1992)], as well as, a process comprising selectively converting one of carboxyl groups into an amide in a similar manner and then passing through a rearrangement reaction of Hofmann type [Tetrahedron Lett., vol. 33, p. 6763 (1992)] are known in the art. However, these processes are also unsuitable for an industrial production because they use an expensive base (e.g. lithium hexamethyldisilazane and lithium amide), an explosive azide compound, a toxic lead compound, or the like.
On the other hand, as a process for preparing 3-amino-2-hydroxypropionic acid derivatives (1) which does not use specially dangerous reagents and is suitable for an industrial production, a process comprising a stereoselective hydrolysis of a dihaloketone derivative derived from an amino acid (JP-A-10/59909) is known in the art. In this process, for example, an erythro form [i.e. (2S,3S)-isomer or (2R,3R)-isomer, respectively] of 3-amino-2-hydroxypropionic acid derivative (1) is predominantly obtained from a (S)-amino acid or (R)-amino acid, but there is a limitation as a process for obtaining a threo form [i.e. (2R,3S)-isomer or (2S,3R)-isomer] of 3-amino-2-hydroxypropionic acid derivative (1) which is a diastereomer of the former compound.
In addition, a process is known in the art which comprises reacting the above erythro form [i.e. (2S,3S)-isomer or (2R,3R)-isomer, respectively] of 3-amino-2-hydroxypropionic acid derivative (1) with a carbonylation agent to obtain an erythro form of an oxazolidinone derivative, and then isomerizing it with a strong base to a threo form [i.e. (2R,3S)-isomer or (2S,3R)-isomer] of the oxazolidinone derivative which is a diastereomer of the former compound (JP-A-09/169,744). However, this process must use phosgene having a very high toxicity as a carbonylation agent, and an expensive base such as an alkali metal or alkaline earth metal alkoxide, an alkali metal amide or an alkyl lithium compound or an alkylmagnesium halide as a strong base. Accordingly, the process is unsuitable for an industrial production.
Accordingly, there is a strong need for establishment of a novel production process suitable for an industrial production of 3-amino-2-hydroxypropionic acid derivatives (1) by a methodology different from that of the prior art, in particular, for establishment of an industrial production process for desired stereoisomeric (e.g. threo) 3-amino-2-hydroxypropionic acid derivatives (1).
In view of the above circumstances, the object of the present invention was to provide a process for preparing 3-amino-2-hydroxypropionic acid derivatives (1) which does not use dangerous reagents, is economically advantageous, and is suitable for an industrial production.